Prenatal exposure to ethanol causes multiple adverse defects in the development of the central nervous system. One of the primary causes of these defects are abnormalities in cellular proliferation. This project is designed to examine the mechanism by which ethanol alters cellular proliferation. The proposed studies will focus on the development of two cortical structures, the neocortex and the hippocampus. In these structures, the proliferation of neuroblasts and glioblasts occurs in two zones that line the lateral ventricles, the ventricular and the subventricular zones. Preliminary evidence shows that ethanol affects these two zones differently. During the first stages of this project, the effects of prenatal exposure to ethanol on the duration of the cell cycle and its constituent phases will be determined. These cytokinetic parameters of cellular proliferation will be characterized using two complementary and reinforcing techniques, fluorescence - activated cell sorting (FACS) of dissociated cells and a double- labeling histochemical procedures to be applied directly to tissue sections. The latter technique relies on the immunocytochemical and autoradiographic localization of two DNA precursors, bromodeoxyuridine and (3H)thymidine, respectively. Also, the effects of different blood ethanol concentrations on proliferative activity will be assessed. Subsequently, biochemical assays and FACS will be used to identify antigens which are specific to proliferating populations. Once identified, these antigens will be used for generating monoclonal or polyclonal antibodies. Subsequently, these antibodies will be used to examine the effects of ethanol on the cell cycle of the specific immunoreactive populations. The proposed studies will enable us examine the differential effects of ethanol on the development of various populations related to functional and morphological classes of neurons and glia. They will provide greater insight into the mechanisms by which ethanol produces developmental defects of the central nervous system.